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Takahashi K, Suzuki S, Kawai-Toyooka H, Yamamoto K, Hamaji T, Ootsuki R, Yamaguchi H, Kawachi M, Higashiyama T, Nozaki H. Reorganization of the ancestral sex-determining regions during the evolution of trioecy in Pleodorina starrii. Commun Biol 2023; 6:590. [PMID: 37296191 PMCID: PMC10256686 DOI: 10.1038/s42003-023-04949-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023] Open
Abstract
The coexistence of three sexual phenotypes (male, female and bisexual) in a single species, 'trioecy', is rarely found in diploid organisms such as flowering plants and invertebrates. However, trioecy in haploid organisms has only recently been reported in a green algal species, Pleodorina starrii. Here, we generated whole-genome data of the three sex phenotypes of P. starrii to reveal a reorganization of the ancestral sex-determining regions (SDRs) in the sex chromosomes: the male and bisexual phenotypes had the same "male SDR" with paralogous gene expansions of the male-determining gene MID, whereas the female phenotype had a "female SDR" with transposition of the female-specific gene FUS1 to autosomal regions. Although the male and bisexual sex phenotypes had the identical male SDR and harbored autosomal FUS1, MID and FUS1 expression during sexual reproduction differed between them. Thus, the coexistence of three sex phenotypes in P. starrii is possible.
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Affiliation(s)
- Kohei Takahashi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shigekatsu Suzuki
- Biodiversity Division, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Hiroko Kawai-Toyooka
- Department of Frontier Bioscience, Hosei University, Kajino-cho, Koganei, Tokyo, 184-8584, Japan
| | - Kayoko Yamamoto
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, 112-8681, Japan
| | - Takashi Hamaji
- Research and Development Initiative, Chuo University, Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Ryo Ootsuki
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, 112-8681, Japan
- Department of Natural Sciences, Faculty of Arts and Sciences, Komazawa University, Komazawa, Setagaya-ku, Tokyo, 154-8525, Japan
| | - Haruyo Yamaguchi
- Biodiversity Division, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Masanobu Kawachi
- Biodiversity Division, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Tetsuya Higashiyama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hisayoshi Nozaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
- Biodiversity Division, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.
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2
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Oyama T, Sonoyama T, Kasai M, Sakai Y, Sunobe T. Bidirectional sex change and plasticity of gonadal phases in the goby Lubricogobius exiguus. JOURNAL OF FISH BIOLOGY 2023; 102:1079-1087. [PMID: 36856167 DOI: 10.1111/jfb.15363] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/24/2023] [Indexed: 05/13/2023]
Abstract
Of the ca. 500 known hermaphroditic fish species, bidirectional sex change and simultaneous hermaphroditism are currently known in 69 and 57 species, respectively. Both bidirectional sex change and simultaneous hermaphroditism are predicted to evolve when mating opportunities are limited, such as in cases of low-density distribution and low mobility of individuals. However, the plasticity of sex is adaptive in obtaining mating opportunities, especially when there is mate loss. Pair-rearing experiments and histological observations of gonads of the goby Lubricogobius exiguus, which has low-density distributions and low mobility, showed bidirectional sex change. The male-role individuals in pairs had gonads in which only the testis was functional (male-phase), whereas the female-role individuals had two types of gonads: only the ovary was functional (female-phase) or both testis and ovary were functional (simultaneously hermaphroditic phase, SH-phase). In addition, single-rearing experiments showed SH-phase gonads in all individuals, and some cyclic spawning but no self-fertilization occurred. These results revealed that L. exiguus has an unusual sexual pattern among hermaphroditic fishes because they undergo bidirectional sex change and some maintain SH-phase gonads. These findings indicate that the low-density distribution and low mobility of L. exiguus in their natural habitat may have influenced the evolution of this unique sexual pattern.
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Affiliation(s)
- Takumi Oyama
- Laboratory of Fish Behavioral Ecology, Tateyama Station, Field Science Center, Tokyo University of Marine Science and Technology, Tateyama, Chiba, Japan
- Laboratory of Biology of Aquatic Resources, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | | | - Miku Kasai
- Shimonoseki Marine Science Museum, Shimonoseki, Yamaguchi, Japan
| | - Yoichi Sakai
- Laboratory of Biology of Aquatic Resources, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Tomoki Sunobe
- Laboratory of Fish Behavioral Ecology, Tateyama Station, Field Science Center, Tokyo University of Marine Science and Technology, Tateyama, Chiba, Japan
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3
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Trioecy is maintained as a time-stable mating system in the pink sea urchin Toxopneustes roseus from the Mexican Pacific. Sci Rep 2022; 12:21408. [PMID: 36496463 PMCID: PMC9741619 DOI: 10.1038/s41598-022-26059-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 12/08/2022] [Indexed: 12/13/2022] Open
Abstract
Trioecy is a sexual system that consists of the co-occurrence of females, males and hermaphrodites in a population and is common in plants; however, in animals it is uncommon and poorly understood. In echinoderms, trioecy had never been recorded until now. Frequencies of females, males, and hermaphrodites were evaluated and gametogenic development was histologically characterized in a population of Toxopneustes roseus inhabiting the Mexican Pacific. Trioecy in this population is functional and temporally stable, since the three sexes coexisted in each sampling month. The hermaphrodites presented similar gametogenic development as the females and males and participated during the spawning season, contributing to the population's reproductive process. Trioecy is considered an evolutionarily transitory state, and it is extremely difficult to explain its presence in a species. We hypothesize that continuous ocean warming represents a threat to the survival of this population of T. roseus, since its early developmental stages, which represent a population bottleneck, are more vulnerable to high temperatures than other sea urchins inhabiting the area, while its population density is significantly lower. These conditions generate a strongly stressed environment, which is the determining factor that maintains the stability of trioecy in the species in which it has been studied.
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4
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Vihinen M. Individual Genetic Heterogeneity. Genes (Basel) 2022; 13:genes13091626. [PMID: 36140794 PMCID: PMC9498725 DOI: 10.3390/genes13091626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 08/25/2022] [Accepted: 09/08/2022] [Indexed: 11/28/2022] Open
Abstract
Genetic variation has been widely covered in literature, however, not from the perspective of an individual in any species. Here, a synthesis of genetic concepts and variations relevant for individual genetic constitution is provided. All the different levels of genetic information and variation are covered, ranging from whether an organism is unmixed or hybrid, has variations in genome, chromosomes, and more locally in DNA regions, to epigenetic variants or alterations in selfish genetic elements. Genetic constitution and heterogeneity of microbiota are highly relevant for health and wellbeing of an individual. Mutation rates vary widely for variation types, e.g., due to the sequence context. Genetic information guides numerous aspects in organisms. Types of inheritance, whether Mendelian or non-Mendelian, zygosity, sexual reproduction, and sex determination are covered. Functions of DNA and functional effects of variations are introduced, along with mechanism that reduce and modulate functional effects, including TARAR countermeasures and intraindividual genetic conflict. TARAR countermeasures for tolerance, avoidance, repair, attenuation, and resistance are essential for life, integrity of genetic information, and gene expression. The genetic composition, effects of variations, and their expression are considered also in diseases and personalized medicine. The text synthesizes knowledge and insight on individual genetic heterogeneity and organizes and systematizes the central concepts.
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Affiliation(s)
- Mauno Vihinen
- Department of Experimental Medical Science, BMC B13, Lund University, SE-22184 Lund, Sweden
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5
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Evolution of sexual systems, sex chromosomes and sex-linked gene transcription in flatworms and roundworms. Nat Commun 2022; 13:3239. [PMID: 35688815 PMCID: PMC9187692 DOI: 10.1038/s41467-022-30578-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 05/06/2022] [Indexed: 12/02/2022] Open
Abstract
Many species with separate male and female individuals (termed ‘gonochorism’ in animals) have sex-linked genome regions. Here, we investigate evolutionary changes when genome regions become completely sex-linked, by analyses of multiple species of flatworms (Platyhelminthes; among which schistosomes recently evolved gonochorism from ancestral hermaphroditism), and roundworms (Nematoda) which have undergone independent translocations of different autosomes. Although neither the evolution of gonochorism nor translocations fusing ancestrally autosomal regions to sex chromosomes causes inevitable loss of recombination, we document that formerly recombining regions show genomic signatures of recombination suppression in both taxa, and become strongly genetically degenerated, with a loss of most genes. Comparisons with hermaphroditic flatworm transcriptomes show masculinisation and some defeminisation in schistosome gonad gene expression. We also find evidence that evolution of sex-linkage in nematodes is accompanied by transcriptional changes and dosage compensation. Our analyses also identify sex-linked genes that could assist future research aimed at controlling some of these important parasites. Transitions between hermaphroditic and separate sexes are relatively understudied in animals compared to pants. Here, Wang et al. reconstruct the evolution of separate sexes in the flatworms and complex changes of sex chromosomes in the roundworms.
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Pla S, Benvenuto C, Capellini I, Piferrer F. Switches, stability and reversals in the evolutionary history of sexual systems in fish. Nat Commun 2022; 13:3029. [PMID: 35637181 PMCID: PMC9151764 DOI: 10.1038/s41467-022-30419-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 04/29/2022] [Indexed: 11/09/2022] Open
Abstract
Sexual systems are highly diverse and have profound consequences for population dynamics and resilience. Yet, little is known about how they evolved. Using phylogenetic Bayesian modelling and a sample of 4614 species, we show that gonochorism is the likely ancestral condition in teleost fish. While all hermaphroditic forms revert quickly to gonochorism, protogyny and simultaneous hermaphroditism are evolutionarily more stable than protandry. In line with theoretical expectations, simultaneous hermaphroditism does not evolve directly from gonochorism but can evolve slowly from sequential hermaphroditism, particularly protandry. We find support for the predictions from life history theory that protogynous, but not protandrous, species live longer than gonochoristic species and invest the least in male gonad mass. The distribution of teleosts' sexual systems on the tree of life does not seem to reflect just adaptive predictions, suggesting that adaptations alone may not fully explain why some sexual forms evolve in some taxa but not others (Williams' paradox). We propose that future studies should incorporate mating systems, spawning behaviours, and the diversity of sex determining mechanisms. Some of the latter might constrain the evolution of hermaphroditism, while the non-duality of the embryological origin of teleost gonads might explain why protogyny predominates over protandry in teleosts.
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Affiliation(s)
- Susanna Pla
- Institut de Ciències del Mar, Spanish National Research Council (CSIC), Barcelona, Spain
| | - Chiara Benvenuto
- School of Science, Engineering and Environment, University of Salford, Salford, UK
| | | | - Francesc Piferrer
- Institut de Ciències del Mar, Spanish National Research Council (CSIC), Barcelona, Spain.
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7
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David P, Degletagne C, Saclier N, Jennan A, Jarne P, Plénet S, Konecny L, François C, Guéguen L, Garcia N, Lefébure T, Luquet E. Extreme mitochondrial DNA divergence underlies genetic conflict over sex determination. Curr Biol 2022; 32:2325-2333.e6. [PMID: 35483362 DOI: 10.1016/j.cub.2022.04.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/28/2022] [Accepted: 04/06/2022] [Indexed: 01/06/2023]
Abstract
Cytoplasmic male sterility (CMS) is a form of genetic conflict over sex determination that results from differences in modes of inheritance between genomic compartments.1-3 Indeed, maternally transmitted (usually mitochondrial) genes sometimes enhance their transmission by suppressing the male function in a hermaphroditic organism to the detriment of biparentally inherited nuclear genes. Therefore, these hermaphrodites become functionally female and may coexist with regular hermaphrodites in so-called gynodioecious populations.3 CMS has been known in plants since Darwin's times4 but is previously unknown in the animal kingdom.5-8 We relate the first observation of CMS in animals. It occurs in a freshwater snail population, where some individuals appear unable to sire offspring in controlled crosses and show anatomical, physiological, and behavioral characters consistent with a suppression of the male function. Male sterility is associated with a mitochondrial lineage that underwent a spectacular acceleration of DNA substitution rates, affecting the entire mitochondrial genome-this acceleration concerns both synonymous and non-synonymous substitutions and therefore results from increased mitogenome mutation rates. Consequently, mitochondrial haplotype divergence within the population is exceptionally high, matching that observed between snail taxa that diverged 475 million years ago. This result is reminiscent of similar accelerations in mitogenome evolution observed in plant clades where gynodioecy is frequent,9,10 both being consistent with arms-race evolution of genome regions implicated in CMS.11,12 Our study shows that genomic conflicts can trigger independent evolution of similar sex-determination systems in plants and animals and dramatically accelerate molecular evolution.
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Affiliation(s)
- Patrice David
- CEFE, CNRS, University of Montpellier, IRD, EPHE, Montpellier, France.
| | - Cyril Degletagne
- University of Lyon, CNRS, ENTPE, UMR5023 LEHNA, 69622 Villeurbanne, France
| | | | - Aurel Jennan
- University of Lyon, CNRS, ENTPE, UMR5023 LEHNA, 69622 Villeurbanne, France
| | - Philippe Jarne
- CEFE, CNRS, University of Montpellier, IRD, EPHE, Montpellier, France
| | - Sandrine Plénet
- University of Lyon, CNRS, ENTPE, UMR5023 LEHNA, 69622 Villeurbanne, France
| | - Lara Konecny
- University of Lyon, CNRS, ENTPE, UMR5023 LEHNA, 69622 Villeurbanne, France
| | | | - Laurent Guéguen
- University of Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France
| | - Noéline Garcia
- University of Lyon, CNRS, ENTPE, UMR5023 LEHNA, 69622 Villeurbanne, France
| | - Tristan Lefébure
- University of Lyon, CNRS, ENTPE, UMR5023 LEHNA, 69622 Villeurbanne, France
| | - Emilien Luquet
- University of Lyon, CNRS, ENTPE, UMR5023 LEHNA, 69622 Villeurbanne, France
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8
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Schärer L. Evolution: Mitochondrial lodgers can take over in hermaphroditic snails. Curr Biol 2022; 32:R477-R479. [PMID: 35609548 DOI: 10.1016/j.cub.2022.04.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Mitochondria - the cell's power stations - are inherited uniparentally via eggs, not sperm. In hermaphroditic plants, they sometimes prevent their hosts from making pollen (and sperm), causing cytoplasmic male sterility. New evidence from a hermaphroditic freshwater snail now documents cytoplasmic male sterility in animals.
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Affiliation(s)
- Lukas Schärer
- Department of Environmental Sciences, University of Basel, Zoological Institute, Vesalgasse 1, 4051 Basel, Switzerland.
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9
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Breton S, Stewart DT, Brémaud J, Havird JC, Smith CH, Hoeh WR. Did doubly uniparental inheritance (DUI) of mtDNA originate as a cytoplasmic male sterility (CMS) system? Bioessays 2022; 44:e2100283. [PMID: 35170770 PMCID: PMC9083018 DOI: 10.1002/bies.202100283] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/26/2022] [Accepted: 01/31/2022] [Indexed: 01/10/2023]
Abstract
Animal and plant species exhibit an astonishing diversity of sexual systems, including environmental and genetic determinants of sex, with the latter including genetic material in the mitochondrial genome. In several hermaphroditic plants for example, sex is determined by an interaction between mitochondrial cytoplasmic male sterility (CMS) genes and nuclear restorer genes. Specifically, CMS involves aberrant mitochondrial genes that prevent pollen development and specific nuclear genes that restore it, leading to a mixture of female (male-sterile) and hermaphroditic individuals in the population (gynodioecy). Such a mitochondrial-nuclear sex determination system is thought to be rare outside plants. Here, we present one possible case of CMS in animals. We hypothesize that the only exception to the strict maternal mtDNA inheritance in animals, the doubly uniparental inheritance (DUI) system in bivalves, might have originated as a mitochondrial-nuclear sex-determination system. We document and explore similarities that exist between DUI and CMS, and we propose various ways to test our hypothesis.
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Affiliation(s)
- Sophie Breton
- Département des sciences biologiques, Université de Montréal, Montréal, Québec, Canada
| | - Donald T Stewart
- Department of Biology, Acadia University, Wolfville, Nova Scotia, Canada
| | - Julie Brémaud
- Département des sciences biologiques, Université de Montréal, Montréal, Québec, Canada
| | - Justin C Havird
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Chase H Smith
- Department of Integrative Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Walter R Hoeh
- Department of Biological Sciences, Kent State University, Kent, Ohio, USA
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10
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Maier AG, Doerig C. “The sexy side of parasites” – how parasites influence host sex and how the sex of the host impacts parasites. Mol Biochem Parasitol 2022; 248:111462. [DOI: 10.1016/j.molbiopara.2022.111462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/01/2022] [Accepted: 02/09/2022] [Indexed: 10/19/2022]
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11
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Calabrese A, Weeks SC. Testing a behavioral model for the maintenance of androdioecy as a result of sexual conflict in the clam shrimp
Eulimnadia dahli. Ethology 2022. [DOI: 10.1111/eth.13266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Sun X, Cheng J. Phylogenetic Signal Dissection of Heterogeneous 28S and 16S rRNA Genes in Spinicaudata (Branchiopoda, Diplostraca). Genes (Basel) 2021; 12:1705. [PMID: 34828311 PMCID: PMC8625258 DOI: 10.3390/genes12111705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/20/2021] [Accepted: 10/26/2021] [Indexed: 12/05/2022] Open
Abstract
It is still a challenge to reconstruct the deep phylogenetic relationships within spinicaudatans, and there are several different competing hypotheses regarding the interrelationships among Eocyzicidae, Cyzicidae s. s., Leptestheriidae, and Limnadiidae of the Suborder Spinicaudata. In order to explore the source of the inconsistencies, we focus on the sequence variation and the structure model of two rRNA genes based on extensive taxa sampling. The comparative sequence analysis revealed heterogeneity across species and the existence of conserved motifs in all spinicaudatan species. The level of intraspecific heterogeneity differed among species, which suggested that some species might have undergone a relaxed concerted evolution with respect to the 28S rRNA gene. The Bayesian analyses were performed on nuclear (28S rRNA, EF1α) and mitochondrial (16S rRNA, COI) genes. Further, we investigated compositional heterogeneity between lineages and assessed the potential for phylogenetic noise compared to signal in the combined data set. Reducing the non-phylogenetic signals and application of optimal rRNA model recovered a topology congruent with inference from the transcriptome data, whereby Limnadiidae was placed as a sister group to Leptestheriidae + Eocyzicidae with high support (topology I). Tests of alternative hypotheses provided implicit support for four competing topologies, and topology I was the best.
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Affiliation(s)
| | - Jinhui Cheng
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, No. 39, Beijing Eastroad, Nanjing 210008, China;
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13
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Molinier C, Boyer L, Villamil N. Digest: Evolution and maintenance of androdioecy in a haplodiploid insect. Evolution 2021; 75:3000-3001. [PMID: 34505287 DOI: 10.1111/evo.14346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/26/2021] [Accepted: 08/29/2021] [Indexed: 11/29/2022]
Abstract
The coexistence of hermaphrodites and males (androdioecy) is rare in both plants and animals and has hitherto remained unknown in insects. Mongue et al. report a new case of androdioecy in the invasive haplodiploid insect Icerya purchasi, in which hermaphrodites can only self-fertilize, but occasionally mate with males. Revealingly, I. purchasi shares several features with other androdioecious species such as the consequences of evolution from separate sexes, low outcrossing rates, and its colonizing habit.
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Affiliation(s)
- Cécile Molinier
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Loreleï Boyer
- CEFE, Univ Montpellier, CNRS, Univ Paul Valéry Montpellier 3, EPHE, IRD, Montpellier, France
| | - Nora Villamil
- Department of Ecology and Evolution, Université de Lausanne, Switzerland
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14
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Kanzaki N, Yamashita T, Lee JS, Shih PY, Ragsdale EJ, Shinya R. Tokorhabditis n. gen. (Rhabditida, Rhabditidae), a comparative nematode model for extremophilic living. Sci Rep 2021; 11:16470. [PMID: 34389775 PMCID: PMC8363662 DOI: 10.1038/s41598-021-95863-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 07/26/2021] [Indexed: 11/09/2022] Open
Abstract
Life in extreme environments is typically studied as a physiological problem, although the existence of extremophilic animals suggests that developmental and behavioral traits might also be adaptive in such environments. Here, we describe a new species of nematode, Tokorhabditis tufae, n. gen., n. sp., which was discovered from the alkaline, hypersaline, and arsenic-rich locale of Mono Lake, California. The new species, which offers a tractable model for studying animal-specific adaptations to extremophilic life, shows a combination of unusual reproductive and developmental traits. Like the recently described sister group Auanema, the species has a trioecious mating system comprising males, females, and self-fertilizing hermaphrodites. Our description of the new genus thus reveals that the origin of this uncommon reproductive mode is even more ancient than previously assumed, and it presents a new comparator for the study of mating-system transitions. However, unlike Auanema and almost all other known rhabditid nematodes, the new species is obligately live-bearing, with embryos that grow in utero, suggesting maternal provisioning during development. Finally, our isolation of two additional, molecularly distinct strains of the new genus-specifically from non-extreme locales-establishes a comparative system for the study of extremophilic traits in this model.
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Affiliation(s)
- Natsumi Kanzaki
- Kansai Research Center, Forestry and Forest Products Research Institute (FFPRI), Kyoto, Kyoto, 612-0855, Japan
| | - Tatsuya Yamashita
- School of Agriculture, Meiji University, Kawasaki, Kanagawa, 214-8571, Japan
| | - James Siho Lee
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Pei-Yin Shih
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, 10027, USA
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, 10027, USA
| | - Erik J Ragsdale
- Department of Biology, Indiana University, 915 E. 3rd Street, Bloomington, IN, 47405, USA
| | - Ryoji Shinya
- School of Agriculture, Meiji University, Kawasaki, Kanagawa, 214-8571, Japan.
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15
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Picard MAL, Vicoso B, Bertrand S, Escriva H. Diversity of Modes of Reproduction and Sex Determination Systems in Invertebrates, and the Putative Contribution of Genetic Conflict. Genes (Basel) 2021; 12:1136. [PMID: 34440310 PMCID: PMC8391622 DOI: 10.3390/genes12081136] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/08/2021] [Accepted: 07/11/2021] [Indexed: 12/30/2022] Open
Abstract
About eight million animal species are estimated to live on Earth, and all except those belonging to one subphylum are invertebrates. Invertebrates are incredibly diverse in their morphologies, life histories, and in the range of the ecological niches that they occupy. A great variety of modes of reproduction and sex determination systems is also observed among them, and their mosaic-distribution across the phylogeny shows that transitions between them occur frequently and rapidly. Genetic conflict in its various forms is a long-standing theory to explain what drives those evolutionary transitions. Here, we review (1) the different modes of reproduction among invertebrate species, highlighting sexual reproduction as the probable ancestral state; (2) the paradoxical diversity of sex determination systems; (3) the different types of genetic conflicts that could drive the evolution of such different systems.
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Affiliation(s)
- Marion Anne Lise Picard
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, 66650 Banyuls-sur-Mer, France; (S.B.); (H.E.)
| | - Beatriz Vicoso
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria;
| | - Stéphanie Bertrand
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, 66650 Banyuls-sur-Mer, France; (S.B.); (H.E.)
| | - Hector Escriva
- Sorbonne Université, CNRS, Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, 66650 Banyuls-sur-Mer, France; (S.B.); (H.E.)
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16
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Takahashi K, Kawai-Toyooka H, Ootsuki R, Hamaji T, Tsuchikane Y, Sekimoto H, Higashiyama T, Nozaki H. Three sex phenotypes in a haploid algal species give insights into the evolutionary transition to a self-compatible mating system. Evolution 2021; 75:2984-2993. [PMID: 34250602 PMCID: PMC9291101 DOI: 10.1111/evo.14306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/17/2021] [Accepted: 06/01/2021] [Indexed: 01/01/2023]
Abstract
Mating systems of haploid species such as fungi, algae, and bryophytes are either heterothallic (self‐incompatible) with two sex phenotypes (male and female, or mating type minus and plus in isogamous species) or homothallic (self‐compatible) with only a bisexual phenotype producing zygotes within a clone. The anisogamous volvocine green alga Pleodorina starrii is a haploid species previously reported to have a heterothallic mating system. Here, we found that two additional culture strains originating from the same water system of P. starrii were taxonomically identified as P. starrii and produced male and female gametes and zygotes within a clone (bisexual). Sequences of rapidly evolving plastid genome regions were identical between the bisexual and unisexual (male or female) P. starrii strains. Intercrossings between the bisexual and unisexual strains demonstrated normal thick‐walled zygotes and high survivability of F1 strains. Thus, these strains belong to the same biological species. Pleodorina starrii has a new haploid mating system that is unique in having three sex phenotypes, namely, male, female, and bisexual. Genetic analyses suggested the existence of autosomal “bisexual factor” locus independent of volvocine male and female determining regions. The present findings increase our understanding of the initial evolutionary step of transition from heterothallism to homothallism.
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Affiliation(s)
- Kohei Takahashi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Hiroko Kawai-Toyooka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.,Current Address: Department of Frontier Bioscience, Faculty of Bioscience and Applied Chemistry, Hosei University, Kajinocho, Koganei-shi, Tokyo, 184-8584, Japan
| | - Ryo Ootsuki
- Department of Natural Sciences, Faculty of Arts and Sciences, Komazawa University, Tokyo, 154-8525, Japan.,Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo, 112-8681, Japan
| | - Takashi Hamaji
- Research and Development Initiative, Chuo University, Tokyo, 112-8551, Japan
| | - Yuki Tsuchikane
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.,Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo, 112-8681, Japan
| | - Hiroyuki Sekimoto
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Tokyo, 112-8681, Japan
| | - Tetsuya Higashiyama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan.,Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, 464-8601, Japan.,Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan
| | - Hisayoshi Nozaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan
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17
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Wang Y, Luo A, Lyu T, Dimitrov D, Xu X, Freckleton RP, Li Y, Su X, Li Y, Liu Y, Sandanov D, Li Q, Hao Z, Liu S, Wang Z. Global distribution and evolutionary transitions of angiosperm sexual systems. Ecol Lett 2021; 24:1835-1847. [PMID: 34121305 DOI: 10.1111/ele.13815] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/01/2021] [Accepted: 05/03/2021] [Indexed: 01/08/2023]
Abstract
Angiosperm sexual systems are fundamental to the evolution and distribution of plant diversity, yet spatiotemporal patterns in angiosperm sexual systems and their drivers remain poorly known. Using data on sexual systems and distributions of 68453 angiosperm species, we present the first global maps of sexual system frequencies and evaluate sexual system evolution during the Cenozoic. Frequencies of dioecy and monoecy increase with latitude, while hermaphrodites are more frequent in warm and arid regions. Transitions to dioecy from other states were higher than to hermaphroditism, but transitions away from dioecy increased since the Cenozoic, suggesting that dioecy is not an evolutionary end point. Transitions between hermaphroditism and dioecy increased, while transitions to monoecy decreased with paleo-temperature when paleo-temperature >0℃. Our study demonstrates the biogeography of angiosperm sexual systems from a macroecological perspective, and enhances our understanding of plant diversity patterns and their response to climate change.
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Affiliation(s)
- Yunyun Wang
- Faculty of Life Science and Technology, Central South University of Forestry and Technology and National Engineering Laboratory for Applied Forest Ecological Technology in Southern China, Changsha, China.,Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Ao Luo
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Tong Lyu
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Dimitar Dimitrov
- Department of Natural History, University Museum of Bergen, University of Bergen, Bergen, Norway
| | - Xiaoting Xu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Robert P Freckleton
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Yaoqi Li
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Xiangyan Su
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Yichao Li
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Yunpeng Liu
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Denis Sandanov
- Institute of General and Experimental Biology, Siberian Branch of Russian Academy of Science, Ulan-Ude, Russia
| | - Qingjun Li
- Laboratory of Ecology and Evolutionary Biology, State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan, China
| | - Zhanqing Hao
- Research Center for Ecology and Environmental Sciences, Xian, China
| | - Shuguang Liu
- Faculty of Life Science and Technology, Central South University of Forestry and Technology and National Engineering Laboratory for Applied Forest Ecological Technology in Southern China, Changsha, China
| | - Zhiheng Wang
- Institute of Ecology and Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
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18
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Muyle A, Bachtrog D, Marais GAB, Turner JMA. Epigenetics drive the evolution of sex chromosomes in animals and plants. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200124. [PMID: 33866802 DOI: 10.1098/rstb.2020.0124] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We review how epigenetics affect sex chromosome evolution in animals and plants. In a few species, sex is determined epigenetically through the action of Y-encoded small RNAs. Epigenetics is also responsible for changing the sex of individuals through time, even in species that carry sex chromosomes, and could favour species adaptation through breeding system plasticity. The Y chromosome accumulates repeats that become epigenetically silenced which leads to an epigenetic conflict with the expression of Y genes and could accelerate Y degeneration. Y heterochromatin can be lost through ageing, which activates transposable elements and lowers male longevity. Y chromosome degeneration has led to the evolution of meiotic sex chromosome inactivation in eutherians (placentals) and marsupials, and dosage compensation mechanisms in animals and plants. X-inactivation convergently evolved in eutherians and marsupials via two independently evolved non-coding RNAs. In Drosophila, male X upregulation by the male specific lethal (MSL) complex can spread to neo-X chromosomes through the transposition of transposable elements that carry an MSL-binding motif. We discuss similarities and possible differences between plants and animals and suggest future directions for this dynamic field of research. This article is part of the theme issue 'How does epigenetics influence the course of evolution?'
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Affiliation(s)
- Aline Muyle
- University of California Irvine, Irvine, CA 92697, USA
| | - Doris Bachtrog
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
| | - Gabriel A B Marais
- Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR 5558, F-69622 Villeurbanne, France.,LEAF- Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Portugal
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19
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Mongue AJ, Michaelides S, Coombe O, Tena A, Kim DS, Normark BB, Gardner A, Hoddle MS, Ross L. Sex, males, and hermaphrodites in the scale insect Icerya purchasi. Evolution 2021; 75:2972-2983. [PMID: 33844310 DOI: 10.1111/evo.14233] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 03/25/2021] [Accepted: 03/27/2021] [Indexed: 11/30/2022]
Abstract
Androdioecy (the coexistence of males and hermaphrodites) is a rare mating system for which the evolutionary dynamics are poorly understood. Here, we investigate the cottony cushion scale, Icerya purchasi, one of only three reported cases of androdioecy in insects. In this species, female-like hermaphrodites have been shown to produce sperm and self-fertilize. However, males are ocassionally observed as well. In a large genetic analysis, we show for the first time that, although self-fertilization appears to be the primary mode of reproduction, rare outbreeding events do occur in natural populations, supporting the hypothesis that hermaphrodites mate with males and hence androdioecy is the mating system of I. purchasi. Thus, this globally invasive pest insect appears to enjoy the colonization advantages of a selfing organism while also benefitting from periodic reintroduction of genetic variation through outbreeding with males.
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Affiliation(s)
- Andrew J Mongue
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom
| | - Sozos Michaelides
- Department of Zoology, University of Oxford, Oxford, OX1 3PS, United Kingdom.,Department of Biology, Concordia University, Montreal, Quebec, H4B 1R6, Canada
| | - Oliver Coombe
- Department of Zoology, University of Oxford, Oxford, OX1 3PS, United Kingdom
| | - Alejandro Tena
- Institut Valencià d'Investigacions Agràries (IVIA), Centre de Protecció Vegetal i Biotecnologia, Unitat d'Entomologia, Moncada, 46113, Spain
| | - Dong-Soon Kim
- Majors in Plant Resource Sciences and Environment, College of Applied Life Science, SARI, Jeju National University, Jeju, 63243, Republic of Korea
| | - Benjamin B Normark
- Department of Biology and Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, 01003
| | - Andy Gardner
- Department of Zoology, University of Oxford, Oxford, OX1 3PS, United Kingdom.,School of Biology, University of St Andrews, Fife, KY16 9TH, United Kingdom
| | - Mark S Hoddle
- Department of Entomology, University of California, Riverside, California, 92521
| | - Laura Ross
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom.,Department of Zoology, University of Oxford, Oxford, OX1 3PS, United Kingdom.,Department of Biology and Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts, 01003
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20
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Yamaguchi S, Iwasa Y. Evolutionary game in an androdioecious population: Coupling of outcrossing and male production. J Theor Biol 2021; 513:110594. [PMID: 33460652 DOI: 10.1016/j.jtbi.2021.110594] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/06/2021] [Accepted: 01/11/2021] [Indexed: 11/29/2022]
Abstract
Androdioecy, the coexistence of hermaphrodites and males, is very rare in vertebrates but occurs in mangrove killifish living in ephemeral or unstable habitats. Hermaphrodites reproduce both by outcrossing with males and by selfing. Outbreeding is advantageous because of inbreeding depression, but it requires encounters with males. The advantages of a propensity for outcrossing among hermaphrodites and the production of males affect each other very strongly. To study the evolutionary coupling of these two aspects, we here analyze a simple evolutionary game for a population composed of three phenotypes: outcrossing-oriented hermaphrodites, selfing-oriented hermaphrodites, and males. Outcrossing-oriented hermaphrodites first attempt to search for males and perform outcrossing if they encounter males. If they fail to encounter males, they reproduce via selfing. Selfing-oriented hermaphrodites simply reproduce by selfing. The replicator dynamics may show bistability, in which both the androdioecious population (with outcrossing-oriented hermaphrodites and males) and the pure hermaphroditic population are locally stable. The model shows the fraction of males is either zero or relatively high (more than 25%), which is not consistent with the observed low fraction of males (less than 5%). To explain this discrepancy, we studied several models including immigration and enforced copulation. We concluded that the observed pattern can be most likely explained by a population dominated by selfing-oriented hermaphrodites receiving immigration of males.
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Affiliation(s)
- Sachi Yamaguchi
- Division of Mathematical Sciences, Tokyo Woman's Christian University, Tokyo, Japan.
| | - Yoh Iwasa
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Hyogo, Japan
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21
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Kobayashi M, Yusa Y, Sekino M. Microsatellite DNA markers applicable to paternity inference in the androdioecious gooseneck barnacle Octolasmis warwickii (Lepadiformes: Poecilasmatidae). Mol Biol Rep 2020; 47:4885-4890. [PMID: 32378167 DOI: 10.1007/s11033-020-05473-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 04/25/2020] [Indexed: 11/26/2022]
Abstract
The gooseneck barnacle Octolasmis warwickii has a rare sexual system called androdioecy, in which hermaphrodites and dwarf males co-occur. It has been hypothesized that dwarf males can coexist with conspecific hermaphrodites when dwarf males are capable of leaving more offspring than hermaphrodites via male reproduction. This hypothesis of reproductive superiority of dwarf males can be validated by comparing the reproductive success between dwarf males and hermaphrodites through DNA marker-based parentage testing. In the present study, we developed microsatellite DNA markers for O. warwickii, and evaluated the power of these markers to infer parentage based on simulation analysis. Using next generation sequencing, we obtained 344 microsatellite sequences suitable for designing primer sets for amplification in polymerase chain reaction (PCR). Of these, we examined the PCR amplification efficiency of 54 primer sets, of which 11 passed our primer screening in a population sample (n = 35). The developed markers exhibited moderate to high levels of polymorphisms, and met Hardy-Weinberg equilibrium with little evidence of significant allelic association to each other. Our simulated paternity inference suggested that the combinational use of the markers allows a high resolution of parentage (success rate of > 99.9%) if all candidate fathers are available.
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Affiliation(s)
- Mayumi Kobayashi
- National Research Institute of Fisheries Science, Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan
| | - Yoichi Yusa
- Division of Natural Sciences, Nara Women's University, Nara, Japan
| | - Masashi Sekino
- National Research Institute of Fisheries Science, Fisheries Research and Education Agency, Yokohama, Kanagawa, Japan.
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22
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Cutter AD. Reproductive transitions in plants and animals: selfing syndrome, sexual selection and speciation. THE NEW PHYTOLOGIST 2019; 224:1080-1094. [PMID: 31336389 DOI: 10.1111/nph.16075] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/17/2019] [Indexed: 05/23/2023]
Abstract
The evolution of predominant self-fertilisation frequently coincides with the evolution of a collection of phenotypes that comprise the 'selfing syndrome', in both plants and animals. Genomic features also display a selfing syndrome. Selfing syndrome traits often involve changes to male and female reproductive characters that were subject to sexual selection and sexual conflict in the obligatorily outcrossing ancestor, including the gametic phase for both plants and animals. Rapid evolution of reproductive traits, due to both relaxed selection and directional selection under the new status of predominant selfing, lays the genetic groundwork for reproductive isolation. Consequently, shifts in sexual selection pressures coupled to transitions to selfing provide a powerful paradigm for investigating the speciation process. Plant and animal studies, however, emphasise distinct selective forces influencing reproductive-mode transitions: genetic transmission advantage to selfing or reproductive assurance outweighing the costs of inbreeding depression vs the costs of males and meiosis. Here, I synthesise links between sexual selection, evolution of selfing and speciation, with particular focus on identifying commonalities and differences between plant and animal systems and pointing to areas warranting further synergy.
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Affiliation(s)
- Asher D Cutter
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
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23
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Cutter AD, Morran LT, Phillips PC. Males, Outcrossing, and Sexual Selection in Caenorhabditis Nematodes. Genetics 2019; 213:27-57. [PMID: 31488593 PMCID: PMC6727802 DOI: 10.1534/genetics.119.300244] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/06/2019] [Indexed: 12/15/2022] Open
Abstract
Males of Caenorhabditis elegans provide a crucial practical tool in the laboratory, but, as the rarer and more finicky sex, have not enjoyed the same depth of research attention as hermaphrodites. Males, however, have attracted the attention of evolutionary biologists who are exploiting the C. elegans system to test longstanding hypotheses about sexual selection, sexual conflict, transitions in reproductive mode, and genome evolution, as well as to make new discoveries about Caenorhabditis organismal biology. Here, we review the evolutionary concepts and data informed by study of males of C. elegans and other Caenorhabditis We give special attention to the important role of sperm cells as a mediator of inter-male competition and male-female conflict that has led to drastic trait divergence across species, despite exceptional phenotypic conservation in many other morphological features. We discuss the evolutionary forces important in the origins of reproductive mode transitions from males being common (gonochorism: females and males) to rare (androdioecy: hermaphrodites and males) and the factors that modulate male frequency in extant androdioecious populations, including the potential influence of selective interference, host-pathogen coevolution, and mutation accumulation. Further, we summarize the consequences of males being common vs rare for adaptation and for trait divergence, trait degradation, and trait dimorphism between the sexes, as well as for molecular evolution of the genome, at both micro-evolutionary and macro-evolutionary timescales. We conclude that C. elegans male biology remains underexploited and that future studies leveraging its extensive experimental resources are poised to discover novel biology and to inform profound questions about animal function and evolution.
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Affiliation(s)
- Asher D Cutter
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario M5S3B2, Canada
| | - Levi T Morran
- Department of Biology, Emory University, Atlanta, Georgia 30322, and
| | - Patrick C Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403
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24
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Chromosome-Wide Evolution and Sex Determination in the Three-Sexed Nematode Auanema rhodensis. G3-GENES GENOMES GENETICS 2019; 9:1211-1230. [PMID: 30770412 PMCID: PMC6469403 DOI: 10.1534/g3.119.0011] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Trioecy, a mating system in which males, females and hermaphrodites co-exist, is a useful system to investigate the origin and maintenance of alternative mating strategies. In the trioecious nematode Auanema rhodensis, males have one X chromosome (XO), whereas females and hermaphrodites have two (XX). The female vs. hermaphrodite sex determination mechanisms have remained elusive. In this study, RNA-seq analyses show a 20% difference between the L2 hermaphrodite and female gene expression profiles. RNAi experiments targeting the DM (doublesex/mab-3) domain transcription factor dmd-10/11 suggest that the hermaphrodite sexual fate requires the upregulation of this gene. The genetic linkage map (GLM) shows that there is chromosome-wide heterozygosity for the X chromosome in F2 hermaphrodite-derived lines originated from crosses between two parental inbred strains. These results confirm the lack of recombination of the X chromosome in hermaphrodites, as previously reported. We also describe conserved chromosome elements (Nigon elements), which have been mostly maintained throughout the evolution of Rhabditina nematodes. The seven-chromosome karyotype of A. rhodensis, instead of the typical six found in other rhabditine species, derives from fusion/rearrangements events involving three Nigon elements. The A. rhodensis X chromosome is the smallest and most polymorphic with the least proportion of conserved genes. This may reflect its atypical mode of father-to-son transmission and its lack of recombination in hermaphrodites and males. In conclusion, this study provides a framework for studying the evolution of chromosomes in rhabditine nematodes, as well as possible mechanisms for the sex determination in a three-sexed species.
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25
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Hobza R, Hudzieczek V, Kubat Z, Cegan R, Vyskot B, Kejnovsky E, Janousek B. Sex and the flower - developmental aspects of sex chromosome evolution. ANNALS OF BOTANY 2018; 122:1085-1101. [PMID: 30032185 PMCID: PMC6324748 DOI: 10.1093/aob/mcy130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/13/2018] [Indexed: 05/07/2023]
Abstract
Background The evolution of dioecious plants is occasionally accompanied by the establishment of sex chromosomes: both XY and ZW systems have been found in plants. Structural studies of sex chromosomes are now being followed up by functional studies that are gradually shedding light on the specific genetic and epigenetic processes that shape the development of separate sexes in plants. Scope This review describes sex determination diversity in plants and the genetic background of dioecy, summarizes recent progress in the investigation of both classical and emerging model dioecious plants and discusses novel findings. The advantages of interspecies hybrids in studies focused on sex determination and the role of epigenetic processes in sexual development are also overviewed. Conclusions We integrate the genic, genomic and epigenetic levels of sex determination and stress the impact of sex chromosome evolution on structural and functional aspects of plant sexual development. We also discuss the impact of dioecy and sex chromosomes on genome structure and expression.
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Affiliation(s)
- Roman Hobza
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Vojtech Hudzieczek
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Zdenek Kubat
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Radim Cegan
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Boris Vyskot
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Eduard Kejnovsky
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
| | - Bohuslav Janousek
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska, Brno, Czech Republic
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26
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Olito C, Abbott JK, Jordan CY. The interaction between sex-specific selection and local adaptation in species without separate sexes. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170426. [PMID: 30150224 PMCID: PMC6125720 DOI: 10.1098/rstb.2017.0426] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2018] [Indexed: 11/12/2022] Open
Abstract
Local adaptation in hermaphrodite species can be based on a variety of fitness components, including survival, as well as both female and male sex-functions within individuals. When selection via female and male fitness components varies spatially (e.g. due to environmental heterogeneity), local adaptation will depend, in part, on variation in selection through each fitness component, and the extent to which genetic trade-offs between sex-functions maintain genetic variation necessary for adaptation. Local adaptation will also depend on the hermaphrodite mating system because self-fertilization alters several key factors influencing selection and the maintenance of genetic variance underlying trade-offs between the sex-functions (sexually antagonistic polymorphism). As a first step to guide intuition regarding sex-specific adaptation in hermaphrodites, we develop a simple theoretical model incorporating the essential features of hermaphrodite mating and adaptation in a spatially heterogeneous environment, and explore the interaction between sex-specific selection, self-fertilization and local adaptation. Our results suggest that opportunities for sex-specific local adaptation in hermaphrodites depend strongly on the extent of self-fertilization and inbreeding depression. Using our model as a conceptual framework, we provide a broad overview of the literature on sex-specific selection and local adaptation in hermaphroditic plants and animals, emphasizing promising future directions in light of our theoretical predictions.This article is part of the theme issue 'Linking local adaptation with the evolution of sex differences'.
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Affiliation(s)
- Colin Olito
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Victoria 3800, Australia
- Department of Biology, Section for Evolutionary Ecology, Lund University, Lund, Sweden
| | - Jessica K Abbott
- Department of Biology, Section for Evolutionary Ecology, Lund University, Lund, Sweden
| | - Crispin Y Jordan
- School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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27
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Dreyer N, Sørensen S, Yusa Y, Sawada K, Nash DR, Svennevig N, Høeg JT. Sex allocation and maintenance of androdioecy in the pedunculated barnacle Scalpellum scalpellum (Crustacea: Cirripedia: Thoracica). Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Niklas Dreyer
- Natural History Museum of Denmark, Zoological Museum, Section for Biosystematics, University of Copenhagen, Universitetsparken, Copenhagen, Denmark
| | - Stefan Sørensen
- Department of Biology, Marine Biological Section, University of Copenhagen, Universitetsparken, Copenhagen, Denmark
| | - Yoichi Yusa
- Nara Women’s University, Kitauoya-nishi, Nara, Japan
| | - Kota Sawada
- Department of Evolutionary Studies of Biosystems, Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa, Japan
| | - David R Nash
- Department of Biology, Section for Ecology and Evolution, University of Copenhagen, Universitetsparken, Copenhagen, Denmark
| | - Niels Svennevig
- Department of Biology, Marine Biological Section, University of Copenhagen, Universitetsparken, Copenhagen, Denmark
| | - Jens T Høeg
- Department of Biology, Marine Biological Section, University of Copenhagen, Universitetsparken, Copenhagen, Denmark
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28
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Ford RE, Weeks SC. Intersexual conflict in androdioecious clam shrimp: Do androdioecious hermaphrodites evolve to avoid mating with males? Ethology 2018. [DOI: 10.1111/eth.12738] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Rebecah E. Ford
- Program In Integrated Biosciences; Department of Biology; The University of Akron; Akron OH USA
| | - Stephen C. Weeks
- Program In Integrated Biosciences; Department of Biology; The University of Akron; Akron OH USA
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Sasson DA, Ryan JF. A reconstruction of sexual modes throughout animal evolution. BMC Evol Biol 2017; 17:242. [PMID: 29207942 PMCID: PMC5717846 DOI: 10.1186/s12862-017-1071-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 11/15/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Although most extant animals have separate sexes, simultaneous hermaphrodites can be found in lineages throughout the animal kingdom. However, the sexual modes of key ancestral nodes including the last common ancestor (LCA) of all animals remain unclear. Without these data, it is difficult to infer the reproductive-state transitions that occurred early in animal evolution, and thus a broad understanding of the evolution of animal reproduction remains elusive. In this study, we use a composite phylogeny from four previously published studies, two alternative topologies (ctenophores or sponges as sister to the rest of animals), and multiple phylogenetic approaches to conduct the most extensive analysis to date of the evolution of animal sexual modes. RESULTS Our analyses clarify the sexual mode of many ancestral animal nodes and allow for sound inferences of modal transitions that have occurred in animal history. Our results also indicate that the transition from separate sexes to hermaphroditism has been more common in animal history than the reverse. CONCLUSIONS These results provide the most complete view of the evolution of animal sexual modes to date and provide a framework for future inquiries into the correlation of these transitions with genes, behaviors, and physiology. These results also suggest that mutations promoting hermaphroditism have historically been more likely to invade gonochoristic populations than vice versa.
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Affiliation(s)
- Daniel A Sasson
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St. Augustine, FL, USA
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Joseph F Ryan
- Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Blvd, St. Augustine, FL, USA.
- Department of Biology, University of Florida, Gainesville, FL, USA.
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30
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Vellnow N, Vizoso DB, Viktorin G, Schärer L. No evidence for strong cytonuclear conflict over sex allocation in a simultaneously hermaphroditic flatworm. BMC Evol Biol 2017; 17:103. [PMID: 28427326 PMCID: PMC5397761 DOI: 10.1186/s12862-017-0952-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 04/10/2017] [Indexed: 01/31/2023] Open
Abstract
Background Cytoplasmic sex allocation distorters, which arise from cytonuclear conflict over the optimal investment into male versus female reproductive function, are some of the best-researched examples for genomic conflict. Among hermaphrodites, many such distorters have been found in plants, while, to our knowledge, none have been clearly documented in animals. Methods Here we provide a quantitative test for cytonuclear conflict over sex allocation in the simultaneously hermaphroditic flatworm Macrostomum lignano. We used a quantitative genetic breeding design, employing pair-wise crosses of 2 × 15 independent inbred lines, to partition the phenotypic variance in several traits (including sex allocation) into its nuclear and cytoplasmic components. Results Although the nuclear genetic background had a significant effect on all traits analyzed, we found significant cytoplasmic genetic variation only for ovary size, there explaining just 4.1% of the variance. A subsequent statistical power analysis showed that the experimental design had considerable power to detect cytonuclear interactions. Conclusion We conclude that there were no strong effects of cytonuclear conflict in the studied populations, possibly because the usually compact mitochondrial genomes in animals have a lower evolvability than the large mitochondrial genomes in plants or because the sampled populations currently do not harbor variation at putative distorter and/or the restorer loci. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0952-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nikolas Vellnow
- University of Basel, Zoological Institute, Evolutionary Biology, Basel, Switzerland.
| | - Dita B Vizoso
- University of Basel, Zoological Institute, Evolutionary Biology, Basel, Switzerland.,University of Innsbruck, Institute of Zoology, Innsbruck, Austria
| | - Gudrun Viktorin
- University of Basel, Zoological Institute, Evolutionary Biology, Basel, Switzerland
| | - Lukas Schärer
- University of Basel, Zoological Institute, Evolutionary Biology, Basel, Switzerland.,University of Innsbruck, Institute of Zoology, Innsbruck, Austria
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31
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Muyle A, Käfer J, Zemp N, Mousset S, Picard F, Marais GA. SEX-DETector: A Probabilistic Approach to Study Sex Chromosomes in Non-Model Organisms. Genome Biol Evol 2016; 8:2530-43. [PMID: 27492231 PMCID: PMC5010906 DOI: 10.1093/gbe/evw172] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We propose a probabilistic framework to infer autosomal and sex-linked genes from RNA-seq data of a cross for any sex chromosome type (XY, ZW, and UV). Sex chromosomes (especially the non-recombining and repeat-dense Y, W, U, and V) are notoriously difficult to sequence. Strategies have been developed to obtain partially assembled sex chromosome sequences. Most of them remain difficult to apply to numerous non-model organisms, either because they require a reference genome, or because they are designed for evolutionarily old systems. Sequencing a cross (parents and progeny) by RNA-seq to study the segregation of alleles and infer sex-linked genes is a cost-efficient strategy, which also provides expression level estimates. However, the lack of a proper statistical framework has limited a broader application of this approach. Tests on empirical Silene data show that our method identifies 20-35% more sex-linked genes than existing pipelines, while making reliable inferences for downstream analyses. Approximately 12 individuals are needed for optimal results based on simulations. For species with an unknown sex-determination system, the method can assess the presence and type (XY vs. ZW) of sex chromosomes through a model comparison strategy. The method is particularly well optimized for sex chromosomes of young or intermediate age, which are expected in thousands of yet unstudied lineages. Any organisms, including non-model ones for which nothing is known a priori, that can be bred in the lab, are suitable for our method. SEX-DETector and its implementation in a Galaxy workflow are made freely available.
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Affiliation(s)
- Aline Muyle
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Jos Käfer
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Niklaus Zemp
- Institute of Integrative Biology (IBZ), ETH Zurich, Zürich, Switzerland
| | - Sylvain Mousset
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Franck Picard
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
| | - Gabriel Ab Marais
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS/Université Lyon 1, Villeurbanne, France
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Poullet N, Vielle A, Gimond C, Carvalho S, Teotónio H, Braendle C. Complex heterochrony underlies the evolution of Caenorhabditis elegans
hermaphrodite sex allocation. Evolution 2016; 70:2357-2369. [DOI: 10.1111/evo.13032] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 07/30/2016] [Accepted: 08/02/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Nausicaa Poullet
- Université Nice Sophia Antipolis, CNRS, Inserm; IBV; Parc Valrose 06100 Nice France
| | - Anne Vielle
- Université Nice Sophia Antipolis, CNRS, Inserm; IBV; Parc Valrose 06100 Nice France
| | - Clotilde Gimond
- Université Nice Sophia Antipolis, CNRS, Inserm; IBV; Parc Valrose 06100 Nice France
| | - Sara Carvalho
- Instituto Gulbenkian de Ciência; Apartado 14 P-2781-901 Oeiras Portugal
| | - Henrique Teotónio
- Institut de Biologie; École Normale Supérieure; CNRS UMR 8197, INSERM U1024 F-75005 Paris France
| | - Christian Braendle
- Université Nice Sophia Antipolis, CNRS, Inserm; IBV; Parc Valrose 06100 Nice France
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33
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Ellis RE. "The persistence of memory"-Hermaphroditism in nematodes. Mol Reprod Dev 2016; 84:144-157. [PMID: 27291983 DOI: 10.1002/mrd.22668] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/01/2016] [Indexed: 12/13/2022]
Abstract
Self-fertility has evolved many times in nematodes. This transition often produces an androdioecious species, with XX hermaphrodites and XO males. Although these hermaphrodites resemble females in most respects, early germ cells differentiate as sperm, and late ones as oocytes. The sperm then receive an activation signal, populate the spermathecae, and are stored for later use in self-fertilization. These traits are controlled by complex modifications to the sex-determination and sperm activation pathways, which have arisen independently during the evolution of each hermaphroditic species. This transformation in reproductive strategy then promotes other major changes in the development, evolution, and population structure of these animals. Mol. Reprod. Dev. 84: 144-157, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ronald E Ellis
- Department of Molecular Biology, Rowan University SOM, Stratford, New Jersey
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34
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Ewers‐Saucedo C, Hope NB, Wares JP. The unexpected mating system of the androdioecious barnacle
Chelonibia testudinaria
(Linnaeus 1758). Mol Ecol 2016; 25:2081-92. [DOI: 10.1111/mec.13593] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/06/2016] [Accepted: 02/17/2016] [Indexed: 02/04/2023]
Affiliation(s)
| | - Neva B. Hope
- Department of Genetics University of Georgia Athens GA 30602 USA
| | - John P. Wares
- Department of Genetics University of Georgia Athens GA 30602 USA
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35
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Weadick CJ, Sommer RJ. Mating System Transitions Drive Life Span Evolution in Pristionchus Nematodes. Am Nat 2016; 187:517-31. [PMID: 27028079 DOI: 10.1086/685283] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Interactions between the sexes influence evolution at many scales, but not all animal species conform to the familiar male-female (dioecious) mating system; such taxa are powerful tools for studying the evolutionary importance of sexual selection and conflict on all manner of life-history traits, including longevity. We tested for an effect of mating system on adult life span in Pristionchus nematodes, where self-fertile hermaphrodites have replaced females multiple times independently throughout the genus (androdioecy). By measuring adult life span for 11 species (6 dioecious, 5 androdioecious), we found that life span is considerably shorter in hermaphrodites relative to closely related females. This effect is not a cost of reproduction; brood size did not reliably trade off with life span in self-fertilizing hermaphrodites or in mated females. Furthermore, we found that sexual dimorphism in life span varied among dioecious species, with females generally outliving males. Finally, we documented intraspecific variation for life span and cuticular disease (blistering) prevalence in Pristionchus pacificus, a model system for evolutionary-developmental biology. This work demonstrates that mating system transitions and life span evolution are linked in Pristionchus nematodes and provides a foundation for future comparative and mechanistic studies of aging in this genus.
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36
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Høeg JT, Yusa Y, Dreyer N. Sex determination in the androdioecious barnacleScalpellum scalpellum(Crustacea: Cirripedia). Biol J Linn Soc Lond 2015. [DOI: 10.1111/bij.12735] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jens T. Høeg
- Marine Biology Section; Department of Biology; University of Copenhagen; Universitetsparken 4 DK-2100 Copenhagen Denmark
| | - Yoichi Yusa
- Faculty of Science; Nara Women's University; Nara 630-8506 Japan
| | - Niklas Dreyer
- Marine Biology Section; Department of Biology; University of Copenhagen; Universitetsparken 4 DK-2100 Copenhagen Denmark
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37
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Mating dynamics in a nematode with three sexes and its evolutionary implications. Sci Rep 2015; 5:17676. [PMID: 26631423 PMCID: PMC4668576 DOI: 10.1038/srep17676] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 11/02/2015] [Indexed: 12/15/2022] Open
Abstract
Nematodes have diverse reproductive strategies, which make them ideal subjects for comparative studies to address how mating systems evolve. Here we present the sex ratios and mating dynamics of the free-living nematode Rhabditis sp. SB347, in which males, females and hermaphrodites co-exist. The three sexes are produced by both selfing and outcrossing, and females tend to appear early in a mother’s progeny. Males prefer mating with females over hermaphrodites, which our results suggest is related to the female-specific production of the sex pheromones ascr#1 and ascr#9. We discuss the parallels between this system and that of parasitic nematodes that exhibit alternation between uniparental and biparental reproduction.
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38
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The origins and evolution of dwarf males and habitat use in thoracican barnacles. Mol Phylogenet Evol 2015; 91:1-11. [DOI: 10.1016/j.ympev.2015.04.026] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 03/18/2015] [Accepted: 04/27/2015] [Indexed: 11/21/2022]
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39
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Abstract
Mitochondrial DNA (mtDNA) is predominantly maternally inherited in eukaryotes. Diverse molecular mechanisms underlying the phenomenon of strict maternal inheritance (SMI) of mtDNA have been described, but the evolutionary forces responsible for its predominance in eukaryotes remain to be elucidated. Exceptions to SMI have been reported in diverse eukaryotic taxa, leading to the prediction that several distinct molecular mechanisms controlling mtDNA transmission are present among the eukaryotes. We propose that these mechanisms will be better understood by studying the deviations from the predominating pattern of SMI. This minireview summarizes studies on eukaryote species with unusual or rare mitochondrial inheritance patterns, i.e., other than the predominant SMI pattern, such as maternal inheritance of stable heteroplasmy, paternal leakage of mtDNA, biparental and strictly paternal inheritance, and doubly uniparental inheritance of mtDNA. The potential genes and mechanisms involved in controlling mitochondrial inheritance in these organisms are discussed. The linkage between mitochondrial inheritance and sex determination is also discussed, given that the atypical systems of mtDNA inheritance examined in this minireview are frequently found in organisms with uncommon sexual systems such as gynodioecy, monoecy, or andromonoecy. The potential of deviations from SMI for facilitating a better understanding of a number of fundamental questions in biology, such as the evolution of mtDNA inheritance, the coevolution of nuclear and mitochondrial genomes, and, perhaps, the role of mitochondria in sex determination, is considerable.
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Affiliation(s)
- Sophie Breton
- a Department of Biological Sciences, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Donald T Stewart
- b Department of Biology, Acadia University, Wolfville, NS B4P 2R6, Canada
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40
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Transition in sexual system and sex chromosome evolution in the tadpole shrimp Triops cancriformis. Heredity (Edinb) 2015; 115:37-46. [PMID: 25757406 PMCID: PMC4815504 DOI: 10.1038/hdy.2015.10] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 12/19/2022] Open
Abstract
Transitions in sexual system and reproductive mode may affect the course of sex chromosome evolution, for instance by altering the strength of sexually antagonistic selection. However, there have been few studies of sex chromosomes in systems where such transitions have been documented. The European tadpole shrimp, Triops cancriformis, has undergone a transition from dioecy to androdioecy (a sexual system where hermaphrodites and males coexist), offering an excellent opportunity to test the impact of this transition on the evolution of sex chromosomes. To identify sex-linked markers, to understand mechanisms of sex determination and to investigate differences between sexual systems, we carried out a genome-wide association study using restriction site-associated DNA sequencing (RAD-seq) of 47 males, females and hermaphrodites from one dioecious and one androdioecious population. We analysed 22.9 Gb of paired-end sequences and identified and scored >3000 high coverage novel genomic RAD markers. Presence–absence of markers, single-nucleotide polymorphism association and read depth identified 52 candidate sex-linked markers. We show that sex is genetically determined in T. cancriformis, with a ZW system conserved across dioecious and androdioecious populations and that hermaphrodites have likely evolved from females. We also show that the structure of the sex chromosomes differs strikingly, with a larger sex-linked region in the dioecious population compared with the androdioecious population.
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41
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Billiard S, Husse L, Lepercq P, Godé C, Bourceaux A, Lepart J, Vernet P, Saumitou-Laprade P. Selfish male-determining element favors the transition from hermaphroditism to androdioecy. Evolution 2015; 69:683-93. [PMID: 25643740 DOI: 10.1111/evo.12613] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 01/09/2015] [Indexed: 11/28/2022]
Abstract
According to the current, widely accepted paradigm, the evolutionary transition from hermaphroditism toward separate sexes occurs in two successive steps: an initial, intermediate step in which unisexual individuals, male or female, sterility mutants coexist with hermaphrodites and a final step that definitively establishes dioecy. Two nonexclusive processes can drive this transition: inbreeding avoidance and reallocation of resources from one sexual function to the other. Here, we report results of controlled crosses between males and hermaphrodites in Phillyrea angustifolia, an androdioecious species with two mutually intercompatible, but intraincompatible groups of hermaphrodites. We observed different segregation patterns that can be explained by: (1) epistatic interactions between two unlinked diallelic loci, determining sex and mating compatibility, and (2) a mutation with pleiotropic effects: female sterility, full compatibility of males with both hermaphrodite incompatibility groups, and complete male-biased sex-ratio distortion in one of the two groups. Modeling shows that these mechanisms can explain the high frequency of males in populations of P. angustifolia and can promote the maintenance of androdioecy without requiring inbreeding depression or resource reallocation. We thus argue that segregation distortion establishes the right conditions for the evolution of cryptic dioecy and potentially initiates the evolution toward separate sexes.
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Affiliation(s)
- Sylvain Billiard
- Unité Evolution, Ecologie et Paléontologie (EEP), UMR CNRS 8198, Université des Sciences et Technologies de Lille-Lille1, F-59655 Villeneuve d'Ascq Cedex, France
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42
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Theologidis I, Chelo IM, Goy C, Teotónio H. Reproductive assurance drives transitions to self-fertilization in experimental Caenorhabditis elegans. BMC Biol 2014; 12:93. [PMID: 25369737 PMCID: PMC4234830 DOI: 10.1186/s12915-014-0093-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/23/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Evolutionary transitions from outcrossing between individuals to selfing are partly responsible for the great diversity of animal and plant reproduction systems. The hypothesis of 'reproductive assurance' suggests that transitions to selfing occur because selfers that are able to reproduce on their own ensure the persistence of populations in environments where mates or pollination agents are unavailable. Here we test this hypothesis by performing experimental evolution in Caenorhabditis elegans. RESULTS We show that self-compatible hermaphrodites provide reproductive assurance to a male-female population facing a novel environment where outcrossing is limiting. Invasions of hermaphrodites in male-female populations, and subsequent experimental evolution in the novel environment, led to successful transitions to selfing and adaptation. Adaptation was not due to the loss of males during transitions, as shown by evolution experiments in exclusively hermaphroditic populations and in male-hermaphrodite populations. Instead, adaptation was due to the displacement of females by hermaphrodites. Genotyping of single-nucleotide polymorphisms further indicated that the observed evolution of selfing rates was not due to selection of standing genetic diversity. Finally, numerical modelling and evolution experiments in male-female populations demonstrate that the improvement of male fitness components may diminish the opportunity for reproductive assurance. CONCLUSIONS Our findings support the hypothesis that reproductive assurance can drive the transition from outcrossing to selfing, and further suggest that the success of transitions to selfing hinges on adaptation of obligate outcrossing populations to the environment where outcrossing was once a limiting factor.
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Abstract
Hermaphrodites combine the male and female sex functions into a single individual, either sequentially or simultaneously. This simple fact means that they exhibit both similarities and differences in the way in which they experience, and respond to, sexual conflict compared to separate-sexed organisms. Here, we focus on clarifying how sexual conflict concepts can be adapted to apply to all anisogamous sexual systems and review unique (or especially important) aspects of sexual conflict in hermaphroditic animals. These include conflicts over the timing of sex change in sequential hermaphrodites, and in simultaneous hermaphrodites, over both sex roles and the postmating manipulation of the sperm recipient by the sperm donor. Extending and applying sexual conflict thinking to hermaphrodites can identify general evolutionary principles and help explain some of the unique reproductive diversity found among animals exhibiting this widespread but to date understudied sexual system.
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Affiliation(s)
- Lukas Schärer
- Evolutionary Biology, Zoological Institute, University of Basel, 4051 Basel, Switzerland
| | - Tim Janicke
- Centre d'Écologie Fonctionnelle et Évolutive, CNRS UMR 5175, 34293 Montpellier Cedex 05, France
| | - Steven A Ramm
- Evolutionary Biology, Bielefeld University, 33615 Bielefeld, Germany
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45
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Weeks SC, Benvenuto C, Reed SK, Duff RJ, Duan ZH, David P. A field test of a model for the stability of androdioecy in the freshwater shrimp, Eulimnadia texana. J Evol Biol 2014; 27:2080-95. [PMID: 25145977 DOI: 10.1111/jeb.12459] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 07/04/2014] [Indexed: 12/01/2022]
Abstract
The evolution of hermaphroditism from dioecy is a poorly studied transition. Androdioecy (the coexistence of males and hermaphrodites) has been suggested as an intermediate step in this evolutionary transition or could be a stable reproductive mode. Freshwater crustaceans in the genus Eulimnadia have reproduced via androdioecy for 24+ million years and thus are excellent organisms to test models of the stability of androdioecy. Two related models that allow for the stable maintenance of males and hermaphrodites rely on the counterbalancing of three life history parameters. We tested these models in the field over three field seasons and compared the results to previous laboratory estimates of these three parameters. Male and hermaphroditic ratios within years were not well predicted using either the simpler original model or a version of this model updated to account for differences between hermaphroditic types ('monogenic' and 'amphigenic' hermaphrodites). Using parameter estimates of the previous year to predict the next year's sex ratios revealed a much better fit to the original relative to the updated version of the model. Therefore, counter to expectations, accounting for differences between the two hermaphroditic types did not improve the fit of these models. At the moment, we lack strong evidence that the long-term maintenance of androdioecy in these crustaceans is the result of a balancing of life history parameters; other factors, such as metapopulation dynamics or evolutionary constraints, may better explain the 24+ million year maintenance of androdioecy in clam shrimp.
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Affiliation(s)
- S C Weeks
- Integrated Bioscience Program, Department of Biology, The University of Akron, Akron, OH, USA
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46
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Henshaw JM, Marshall DJ, Jennions MD, Kokko H. Local gamete competition explains sex allocation and fertilization strategies in the sea. Am Nat 2014; 184:E32-49. [PMID: 25058290 DOI: 10.1086/676641] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Within and across taxa, there is much variation in the mode of fertilization, that is, whether eggs and/or sperm are released or kept inside or on the surface of the parent's body. Although the evolutionary consequences of fertilization mode are far-reaching, transitions in the fertilization mode itself have largely escaped theoretical attention. Here we develop the first evolutionary model of egg retention and release, which also considers transitions between hermaphroditism and dioecy as well as egg size evolution. We provide a unifying explanation for reported associations between small body size, hermaphroditism, and egg retention in marine invertebrates that have puzzled researchers for more than 3 decades. Our model, by including sperm limitation, shows that all these patterns can arise as an evolutionary response to local competition between eggs for fertilization. This can provide a general explanation for three empirical patterns: sperm casters tend to be smaller than related broadcast spawners, hermaphroditism is disproportionately common in sperm casters, and offspring of sperm casters are larger. Local gamete competition also explains a universal sexual asymmetry: females of some species retain their gametes while males release theirs, but the opposite ("egg casting") lacks evolutionary stability and is apparently not found in nature.
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Affiliation(s)
- Jonathan M Henshaw
- Research School of Biology, Australian National University, Australian Capital Territory 0200, Australia
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47
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Armoza-Zvuloni R, Kramarsky-Winter E, Loya Y, Schlesinger A, Rosenfeld H. Trioecy, a Unique Breeding Strategy in the Sea Anemone Aiptasia diaphana and Its Association with Sex Steroids1. Biol Reprod 2014; 90:122. [DOI: 10.1095/biolreprod.113.114116] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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48
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Choudhury BI, Khan ML, Dayanandan S. Functional androdioecy in critically endangered Gymnocladus assamicus (Leguminosae) in the Eastern Himalayan Region of Northeast India. PLoS One 2014; 9:e87287. [PMID: 24586267 PMCID: PMC3938411 DOI: 10.1371/journal.pone.0087287] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 12/20/2013] [Indexed: 11/18/2022] Open
Abstract
Gymnocladus assamicus is a critically endangered tree species endemic to Northeast India, and shows sexual dimorphism with male and hermaphrodite flowers on separate trees. We studied phenology, reproductive biology and mating system of the species. The flowers are small, tubular, odorless and last for about 96 hours. Pollen grains in both morphs were viable and capable of fertilization leading to fruit and seed set. Scanning electron micrographs revealed morphologically similar pollen in both male and hermaphrodite flowers. The fruit set in open pollinated flowers was 43.61 percent, while controlled autogamous and geitonogamous pollinations yielded 76.81 and 65.58 percent fruit set respectively. Xenogamous pollinations between male and hermaphrodite flowers resulted in 56.85 percent fruit set and pollinations between hermaphrodite flowers yielded 67.90 percent fruit set. This indicates a functionally androdioecious mating system and pollination limited fruit set in G. assamicus. Phylogenetic analyses of Gymnocladus and the sister genus Gleditsia are needed to assess if the androdioecious mating system in G. assamicus evolved from dioecy as a result of selection for hermaphrodites for reproductive assurance during colonization of pollination limited high altitude ecosystems.
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Affiliation(s)
- Baharul Islam Choudhury
- Forest and Evolutionary Genomics Laboratory, and Centre for Structural and Functional Genomics, Biology Department, Concordia University, Quebec, Canada
- Québec Centre for Biodiversity Sciences, Montréal, Quebec, Canada
- Department of Forestry, North Eastern Regional Institute of Science & Technology, Nirjuli, Arunachal Pradesh, India
| | - Mohammed Latif Khan
- Department of Forestry, North Eastern Regional Institute of Science & Technology, Nirjuli, Arunachal Pradesh, India
| | - Selvadurai Dayanandan
- Forest and Evolutionary Genomics Laboratory, and Centre for Structural and Functional Genomics, Biology Department, Concordia University, Quebec, Canada
- Québec Centre for Biodiversity Sciences, Montréal, Quebec, Canada
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Weeks SC, Brantner JS, Astrop TI, Ott DW, Rabet N. The Evolution of Hermaphroditism from Dioecy in Crustaceans: Selfing Hermaphroditism Described in a Fourth Spinicaudatan Genus. Evol Biol 2013. [DOI: 10.1007/s11692-013-9265-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Leonard JL. Williams' paradox and the role of phenotypic plasticity in sexual systems. Integr Comp Biol 2013; 53:671-88. [PMID: 23970358 DOI: 10.1093/icb/ict088] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
As George Williams pointed out in 1975, although evolutionary explanations, based on selection acting on individuals, have been developed for the advantages of simultaneous hermaphroditism, sequential hermaphroditism and gonochorism, none of these evolutionary explanations adequately explains the current distribution of these sexual systems within the Metazoa (Williams' Paradox). As Williams further pointed out, the current distribution of sexual systems is explained largely by phylogeny. Since 1975, we have made a great deal of empirical and theoretical progress in understanding sexual systems. However, we still lack a theory that explains the current distribution of sexual systems in animals and we do not understand the evolutionary transitions between hermaphroditism and gonochorism. Empirical data, collected over the past 40 years, demonstrate that gender may have more phenotypic plasticity than was previously realized. We know that not only sequential hermaphrodites, but also simultaneous hermaphrodites have phenotypic plasticity that alters sex allocation in response to social and environmental conditions. A focus on phenotypic plasticity suggests that one sees a continuum in animals between genetically determined gonochorism on the one hand and simultaneous hermaphroditism on the other, with various types of sequential hermaphroditism and environmental sex determination as points along the spectrum. Here I suggest that perhaps the reason we have been unable to resolve Williams' Paradox is because the problem was not correctly framed. First, because, for example, simultaneous hermaphroditism provides reproductive assurance or dioecy ensures outcrossing does not mean that there are no other evolutionary paths that can provide adaptive responses to those selective pressures. Second, perhaps the question we need to ask is: What selective forces favor increased versus reduced phenotypic plasticity in gender expression? It is time to begin to look at the question of sexual system as one of understanding the timing and degree of phenotypic plasticity in gender expression in the life history in terms of selection acting on a continuum, rather than on a set of discrete sexual systems.
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Affiliation(s)
- Janet L Leonard
- Joseph M. Long Marine Laboratory, University of California-Santa Cruz, Santa Cruz, CA 95060, USA
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